1. Field of the Invention
This invention relates to a balloon catheter for an intra-aortic balloon pump apparatus and, more particularly, to a balloon catheter for an intra-aortic balloon pump apparatus which measures accurate blood pressure at dwelled position of a catheter introduced percutaneously and ensures a hollow portion to utilize for injecting medicament fluid or extracting blood and the like when the catheter is used.
2. Description of the Related Arts
Intra-aortic balloon pumping is the supplemental circulation method aiding the cardiac function to treat the deterioration of cardiac function of a patient such as heart failure. The function of the intra-aortic balloon pumping is completed by inserting a balloon catheter into the aorta of a patient, inputting or outputting the pressurized fluid through catheter tube to said balloon using drive device complying with the cardiac pulsation, and inflating and deflating the balloon.
Double lumen balloon catheter shown in FIG. 6 is employed in a conventional arrangement of intra-aortic balloon pump. This conventional balloon catheter is comprised of central tube 2 in the hollow catheter tube 1. The central tube 2 is penetrated through a wing of Y-shaped connector, and through said catheter tube 1 and a balloon. A first lumen 3 formed between the catheter tube 1 and the central tube 2 serves as a passageway for supplying helium gas into the balloon 4. A second lumen 5 located in the hollow portion of the central tube 2 is used for a guide way for the guide wire. Since the second lumen 5 is connected to the blood vessel at the distal end, the pressure in the second lumen 5 is measured by a blood sensor secured to a proximal end via the second lumen and a separately provided extension tube. The timing of inflating and deflating the balloon is set referring to the blood pressure wave form measured by said blood sensor connected to said extension tube.
However, the obtained result from the conventional method mentioned above is insufficient to set an accurate timing of inflating and deflating the balloon complying with the cardiac pulsation. The blood pressure wave form obtained from the method above has some delay and inaccuracy compared to the original blood pressure wave form at the dwelled position of the balloon, due to the measurement at the other end of the long and narrow second lumen 5 and the separately provided extension tube.
As a solution of the problems mentioned above, a device shown in a Japan Patent Laid-open Publication S61-48346 (published on Mar. 10, 1986) is disclosed. A pressure sensor is disposed on the tip of the balloon catheter, and the signal from said pressure sensor is outputted from the patient""s body to the outside thereof via the catheter according to said conventional prior art.
Another Japan Patent Laid-open Publication S62-189049 (published on Aug. 18, 1987) discloses the means utilizing the aforementioned second lumen formed in the double lumen balloon catheter. In this prior art, the catheter is first inserted percutaneously into the patient""s body and then a special catheter on tip end of which a pressure sensor is provided is inserted through the second lumen of the catheter until the pressure sensor reaches to the tip end of the balloon catheter.
Above-mentioned previous prior arts have the following disadvantages. Since the method according to the Japan Patent Laid-open Publication S61-48346 shows the single lumen structure with no provision of a second lumen for inserting the guide wire to the balloon catheter into the blood vessel, the percutaneous introduction of the catheter into the patient""s body is difficult.
Aforementioned catheter equipped with the pressure sensor according to Japan Patent Laid-open Publication S62-189049 requires additional time and process for supplementary introduction of said catheter with the pressure sensor into said second lumen, which becomes a disadvantage in a critical emergency case.
Since said second lumen has been occupied with said special catheter provided with a pressure sensor after the special catheter is introduced into the patient""s body, the second lumen cannot be utilized when intra-aortic balloon pumping is applied. For instance, medicament fluid cannot be injected into the blood vessel through the second lumen and blood cannot be extracted when said special catheter with pressure sensor is applied.
Accordingly, an object of this invention is to enable the accurate measurement of blood pressure at predetermined position of the balloon by intra-aortic balloon pump introduced percutaneously and to ensure the second lumen with a double lumen structure.
To resolve the foregoing problems the following technical means is provided with the balloon catheter of this invention which includes: a Y-shaped connector having a gas supply port and an electric circuit, a hollow catheter tube one end of which is connected to said connector, a balloon one end of which is connected to the other end of said catheter tube, a hollow central tube inserted into said catheter and serving as a passageway for a guide wire to be inserted into a blood vessel of a patient""s body, the hollow central tube being extending outwardly from the other end of said catheter tube, a top end chip provided on one tip end of the hollow central tube on the balloon side for connecting the balloon to the hollow central tube, a pressure detecting element provided in the top end chip for detecting the pressure at the outer surface of said top end chip, and a connecting device for transmitting the output signals from said pressure detecting element to an external control device.
This invention of intra-aortic balloon pump is capable of measuring the accurate blood pressure with percutaneous means and ensuring the second lumen while using the catheter.
Under this invention of intra-aortic balloon catheter, said connecting device which transmits the output signal from pressure detecting element to an external control device is capable of installation and removal of said balloon catheter.
Reducing the weight and minimizing the bulk of the Y-shaped connector reduce the undesired trouble such as bending the catheter or the cable being caught by other objects, and facilitate the handling.
This invention of intra-aortic balloon catheter is provided with the electric circuit between said pressure detecting element and said connecting device to compensate for the characteristics of said pressure detecting element.
Said electric circuit provides high-accuracy pressure sensor by compensating for the temperature, sensitivity, and zero potential.
Said central tube is provided with two hollow portions (lumen), and said signal line is disposed in one of the hollow portions.
Said signal line is avoided from contacting the blood or water content because said signal line is not disposed in the lumen that serves as a passageway for introducing a guide wire, injecting medicament fluid, or extracting the blood.